Both the Ravens and the Steelers are saying all the polite things about Pittsburgh’s new starting quarterback Byron Leftwich, who is one of the classiest individuals you’ll find in the NFL.

Ravens coach John Harbaugh even went as far as describing Leftwich as having been a “premier” quarterback early in his career with the Jacksonville Jaguars, but we all know better. The numbers don’t lie as Leftwich makes his first NFL start since 2009 and possesses a 79.5 passer rating over the course of a disappointing career for the seventh overall pick of the 2003 draft.

If Pittsburgh is to have a chance to beat the Ravens on Sunday night, it’s going to be because Leftwich doesn’t lose the game and the Steelers’ other facets are able to pick up the slack for the depleted passing game. Instead of the frequent throwing seen from Ben Roethlisberger in recent years, the Baltimore defense will likely deal with a ball-control attack from the league’s 21st-ranked run offense.

“We are just doing the best we can with the guys that we have that are healthy,” Steelers coach Mike Tomlin said. “The quarterback situation is the quarterback situation. The guys that play running back are going to do that, and nothing is going to change in terms of what is expected from them.”

Despite underwhelming averages of 103.8 rushing yards per game and a 3.8 yards per carry, the Steelers’ by-committee approach — based largely on injuries — has improved in recent weeks as running backs have turned in 100-yard performances in three of their last four games. The key to their improvement has been the offensive line, which is still far from an elite unit but is playing better than it has in recent seasons.

In contrast, the Ravens defense ranks 26th against the run and has struggled throughout the season to slow teams using a run-heavy approach, including Kansas City, Dallas, and Houston.

“First of all, it starts with the offensive line,” Harbaugh said. “Their offensive line is a big, physical offensive line. They maul you. That’s their whole thing. The backs are downhill backs. Both [Jonathan] Dwyer and [Isaac] Redman are hard-running guys — very difficult to tackle. You have to wrap them and take them to the ground. You’ve got to gang-tackle, those kinds of things.”

As Pittsburgh has dealt with various injuries at the running back position, the Ravens’ front seven has been decimated with the long-term loss of Ray Lewis, the decreased production from an injured Haloti Ngata, and the early-season absence of Terrell Suggs. Until recently, defensive coordinator Dean Pees had received little from younger players, but the likes of defensive lineman DeAngelo Tyson and linebackers Courtney Upshaw and Paul Kruger have emerged since the bye week to contribute to an improved defensive attack up front.

The yardage totals against Cleveland and Oakland weren’t overly impressive, but the Ravens’ 27th-ranked defense ranks first in the league in red-zone defense with opponents scoring touchdowns in only 36.1 percent of their trips inside the Baltimore 20-yard line. The Browns and Raiders went a combined 0-for-8 in trying to score touchdowns inside the red zone as the “bend but don’t break” mantra becomes more popular in the second half of the season.

Even with the big-play threat of wide receiver Mike Wallace on the outside, Leftwich’s limitations make it unlikely that Pittsburgh can strike quickly, meaning the Steelers will need to sustain drives and move the ball with modest gains. The Ravens will simply try to continue the trend started in recent weeks by clamping down inside the 20 should the Steelers be able to move the ball on the ground.

“You don’t want to do something one week and then not do it the next,” Suggs said. “We fared pretty well the last two weeks, and we’re just trying to keep it going. It’s nothing to be happy about. We’re just going to keep trying to get better around here.”

The Ravens’ preparation doesn’t change with Leftwich at the helm instead of Roethlisberger, but outsiders’ expectations have been altered dramatically for the type of offensive attack the Steelers will have on display. The Pittsburgh of yesteryear will return with a mentality of “three yards and a cloud of dust” with its running game instead of the passing game being on full display.

In past seasons, that would have played perfectly into the hands of the Ravens defense, but that unit will need to prove it can slow the run in order to set up the offense with good field position against an imposing defense on the opposing side.

The names have changed — along with strengths and strategies in the various phases — but the Ravens are expecting another fight in Pittsburgh, even with Roethlisberger on the sideline.

And they wouldn’t have it any other way.

“As soon as we walk in their stadium, they’re going to lock the gates,” Suggs said. “But that’s what we want. We definitely want them to lock the gates behind us so we can get in there and we can have it out. When the clock reads 0:00, we’ll just see what happens. We’ll see how it goes.”